For example, in an apparatus incorporating plural recording head units, such as an ink-jet recording apparatus, as shown in FIG. 5, driving data for jetting ink is sent as serial data or parallel data, from image developing circuit board 101, serving as a host, to head driving circuits (which are slave circuits 102) of each recording head. In this structure, when the number of recording head units increases, the number of connectors is also increased, to connect image developing circuit 101 and slave circuit 102, which results in the increase of transmission lines. Due to this, the scale of the circuit, and the size of the circuit board increase, leading to increased cost.
In recent years, as shown in FIG. 6, a technology is developed in which “n” pieces of recording element circuit boards and head pads, for connecting these recording heads each other and for connecting a printer to these recording element circuit boards, are daisy-chain-connected, which is disclosed in Unexamined Japanese Patent Application Publication No. 2002-67290. In FIG. 6, concerning heater power supply VH, GND, as well as Latch signal and CLK signal, since the same ones are to be applied onto each “n” pieces of recording element circuits, they are branched in a flexible wiring circuit board from a single head pad, and applied onto each recording element circuit board. The head pads are not illustrated in FIG. 6. On the other hand, DATA being an image data, and Heat signal for defining a conducting time of the heater are applied onto each recording element circuit board respectively, because recording image formation and optimum driving operation is conducted for each recording element circuit board. In order to apply different signals onto each recording element circuit board, two head pads 201 and 202 are provided on each recording element circuit board. Temperature sensor output terminal 124 and memory (which is a element characteristic) output terminal 123 are daisy-chain-connected to temperature sensor input terminal 122 and memory input terminal 121, of each adjoining recording element circuit board, respectively by flexible wirings. Further, concerning a recording element circuit board which has no adjoining recording element circuit board, which is an up-front recording element circuit board, its temperature sensor input terminal 122 and memory input terminal 121 are connected to VSS, and wirings are led out from temperature sensor output terminal 124 and memory output terminal 123 of a lattermost recording element circuit board, and which are connected to two head pads 210 of Memory Out and Temp. Out.
However, as shown in FIG. 6, while recording heads are daisy-chain-connected, the data element characteristic and the temperature sensor output are transferred through a shift register. Due to this, large delay is occurred for transferring them to the latter recording heads, and it is very difficult to transfer them in a real time. Further, since the image data is also transferred through a shift register by the same method as above, the delay occurs, and operation must wait until the data is completely transferred to each recording head. Therefore, it is very difficult to conduct the real time control, and the recording apparatus cannot operate at high speed.